Pyridyl amines have been used to prepare Group 4 complexes which are useful transition metal components for use in the polymerization of alkenes, see for example US 2002/0142912; U.S. Pat. No. 6,900,321; and U.S. Pat. No. 6,103,657, where the ligands have been used in complexes in which the ligands are coordinated in a bidentate fashion to the transition metal atom.
WO 2005/095469 shows catalyst compounds that use tridentate ligands through two nitrogen atoms (one amido and one pyridyl) and one oxygen atom.
US 2004/0220050A1 and WO 2007/067965 disclose complexes in which the ligand is coordinated in a tridentate fashion through two nitrogen (one amido and one pyridyl) and one carbon (aryl anion) donors.
A key step in the activation of these complexes is the insertion of an alkene into the metal-aryl bond of the catalyst precursor (Froese, R. D. J. et al., J. Am. Chem. Soc. 2007, 129, pp. 7831-7840) to form an active catalyst that has both five-membered and a seven-membered chelate rings.
WO 2010/037059 discloses pyridine containing amines for use in pharmaceutical applications.
US 2010/0227990 A1 discloses ligands that bind to the metal center with a NNC donor set instead of an NNN or NNP donor set.
WO/0238628 A2 discloses ligands that bind to the metal center with a NNC donor set instead of an NNN or NNP donor set.
Guerin, F.; McConville, D. H.; Vittal, J. J. Organometallics 1996, 15, p. 5586 discloses a ligand family and group 4 complexes that use a NNN-donor set, but do not feature 7-membered chelate ring or either of dihydroindenyl- and tetrahydronaphthalenyl-groups.
U.S. Pat. No. 7,973,116, U.S. Pat. No. 8,394,902, US 2011-0224391, US 2011-0301310 A1, and U.S. Ser. No. 61/815,065, filed Apr. 23, 2013 disclose pyridylamido transition metal complexes that do not feature dihydroindenyl- or tetrahydronaphthalenyl-groups.
References of interest also include: 1) Vaughan, A; Davis, D. S.; Hagadorn, J. R. in Comprehensive Polymer Science, Vol. 3, Chapter 20, “Industrial catalysts for alkene polymerization”; 2) Gibson, V. C.; Spitzmesser, S. K. Chem. Rev. 2003, 103, 283; 3) Britovsek, G. J. P.; Gibson, V. C.; Wass, D. F. Angew. Chem. Int. Ed. 1999, 38, 428; 4) WO 2006/036748; 5) McGuire, R. et al. Coordination Chemistry Reviews, Vol 254, No. 21-22, pages 2574-2583 (2010); 6) U.S. Pat. No. 4,540,753; 7) U.S. Pat. No. 4,804,794; 8) P. Chem. Rev. 2013, 113, 3836-38-57; 9) J. Am. Chem. Soc. 2005, 127, 9913-9923; 10) Lub. Sci. 1989, 1, 265-280; 11) Lubricant Additives, Chemistry and Applications, pages 293-327, CRC Press, 2003; 12) Chemistry and Technology of Lubricants, 3rd edition, pages 153-187, Springer, 2010; 13) US2013-0131294.
U.S. Ser. No. 61/904,551, filed Nov. 15, 2013 discloses pyridyldiamide catalyst compositions that, the instant inventors have found, produce polymers useful in viscosity modification applications.
Lubrication fluids are applied between moving surfaces to reduce friction, thereby improving efficiency and reducing wear. Lubrication fluids also often function to dissipate the heat generated by moving surfaces.
One type of lubrication fluid is a petroleum-based lubrication oil used for internal combustion engines. Lubrication oils contain additives that help the lubrication oil to have a certain viscosity at a given temperature. In general, the viscosity of lubrication oils and fluids is inversely dependent upon temperature. When the temperature of a lubrication fluid is increased, the viscosity generally decreases, and when the temperature is decreased, the viscosity generally increases. For internal combustion engines, for example, it is desirable to have a lower viscosity at low temperatures to facilitate engine starting during cold weather, and a higher viscosity at higher ambient temperatures when lubrication properties typically decline.
Additives for lubrication fluids and oils include rheology modifiers, such as viscosity index (VI) improvers. VI improving components, many of which are derived from ethylene-alpha-olefin copolymers, modify the rheological behavior of a lubricant to increase viscosity and promote a more constant viscosity over the range of temperatures at which the lubricant is used. Higher ethylene content copolymers are thought to efficiently promote oil thickening and shear stability. However, higher ethylene content copolymers also tend to flocculate or aggregate in oil formulations leading to extremely viscous and, in the limit, solid formulations. Flocculation typically happens at ambient or subambient conditions of controlled and quiescent cooling. This deleterious property of otherwise advantageous higher ethylene content viscosity improvers is measured by low temperature solution rheology. Various remedies have been proposed for these higher ethylene content copolymer formulations to overcome or mitigate the propensity towards the formation of high viscosity flocculated materials.
It is anticipated that the performance of VI improvers can be substantially improved, as measured by the thickening efficiency (TE) and the shear stability index (SSI), by appropriate and careful manipulation of the structure of the VI improver.
One proposed solution is the use of blends of amorphous and semi-crystalline ethylene-based copolymers for lubricant oil formulations. The combination of two such ethylene-propylene copolymers allows for increased thickening efficiency, shear stability index, low temperature viscosity performance and pour point. See, e.g., U.S. Pat. Nos. 7,402,235 and 5,391,617, and European Patent 0 638,611, the disclosures of which are incorporated herein by reference.
There remains a need, however, for novel rheology modifier compositions comprised of ethylene and alpha-olefin-based comonomers suitable for use in VI improvers which have unexpectedly good high temperature thermal-oxidative stability, high temperature corrosion resistance, low frictional property, low cold crank viscosity, and low gelation property while still having excellent low temperature solution rheological properties. The present invention meets this and other needs.